Article

Incidence and Predictors of Seizures in Patients with Alzheimer's Disease

Department of Neurology, Columbia University College of Physicians and Surgeons, New York, New York, USA.
Epilepsia (Impact Factor: 4.57). 06/2006; 47(5):867-72. DOI: 10.1111/j.1528-1167.2006.00554.x
Source: PubMed

ABSTRACT

To determine cumulative incidence and predictors of new-onset seizures in mild Alzheimer's disease (AD) with a cohort followed prospectively. Limited information is available on the incidence of seizures, and no reports exist of seizure predictors in AD patients.
Mild AD patients were prospectively followed at 6-month intervals to estimate incidence of unprovoked seizures, compare age-specific risk of unprovoked seizures with population norms, and identify characteristics at baseline (demographics, duration and severity of AD, physical and diagnostic test findings, and comorbid medical and psychiatric conditions) influencing unprovoked seizure risk. Review of study charts and medical records supplemented coded end-point data.
The cumulative incidence of unprovoked seizures at 7 years was nearly 8%. In all age groups, risk was increased compared with a standard population, with an 87-fold increase in the youngest group (age 50-59 years) and more than a threefold increase in the oldest group (age 85+ years). In multivariate modeling, independent predictors of unprovoked seizures were younger age [relative risk (RR), 0.89 per year increase in age; 95% confidence interval (CI), 0.82-0.97], African-American ethnic background (RR, 7.35; 95% CI, 1.42-37.98), more-severe dementia (RR, 4.15; 95% CI, 1.06-16.27), and focal epileptiform findings on electroencephalogram (EEG) (RR, 73.36; 95% CI, 1.75-3075.25).
Seizure incidence is increased in people starting with mild-to-moderate AD. Younger individuals, African Americans, and those with more-severe disease or focal epileptiform findings on EEG were more likely to have unprovoked seizures.

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    • "The risk of unprovoked epileptic seizures is rather high in earlyonset (often familial) Alzheimer's disease, perhaps as much as ~ 90- fold higher than in an age-matched reference population (Amatniek et al., 2006). Importantly, epileptic activity may also be more prevalent in the early stages of 'sporadic' late-onset AD than was previously thought (Vossel et al., 2013), but the underlying mechanisms are poorly understood. "
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    • "Amongst early events linked to AD pathogenesis that can contribute to memory decline, we focused here on neuronal network hypersynchrony (Bakker et al., 2012; Vossel et al., 2013). Indeed, seizures are more frequent in AD patients than in age-matched individuals and seizures can precede the onset of memory deficits (Amatniek et al., 2006; Sanchez et al., 2012). Different lines of evidence also indicate the occurrence of hypersynchronous network activity such as seizures amongst mouse models of AD (Palop et al., 2007; Minkeviciene et al., 2009; Born et al., 2014; Ittner et al., 2014). "
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    • "The prevalence of seizures in AD varies between studies, but is in the range of 10–22 % (Mendez and Lim 2003). Seizure susceptibility increases with progression of the disease (Romanelli et al. 1990), and seizures are more frequent in patients with early disease onset (Amatniek et al. 2006). Amnestic episodes in patients are associated with seizures recorded by EEG, indicating that seizures not only are a concomitant phenomenon of AD, but may actually contribute to the symptoms of dementia (Rabinowicz et al. 2000). "
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